what's the best fat for gf flours to keep them shelf stable?

I'm using olive oil in a cookie that is super moist and then it dries out and gets crumbly about 2 days later, even when kept sealed. Any suggestions about switching out for a more shelf stable fat, like palm oil or butter?

Besides coconut oil, butter or vegan butter (such as Earth Balance) work very well in gluten-free cookies. I find those three fats are the best for gluten-free cookies when it comes to keeping them soft. If you're making something more like brownies or cake, use canola oil. For examples, see my two recipes here: